Manufacture of twist-drills



Patented Mar.'6,18831 N PETERS Pnmummm, wmun m D. c.

(No Model.)

3., E. W.,& E. O. STRANGE.

MANUPAGTURE 0F TWIST DRILLS.

, i718 s'ses:

V UNITED STATES ELIAS STRANGE, ELIAS W. STRANGE, AND EMERSON G. STRANGE,

TAUNTON, MASSACHUSETTS.

PATENT omca MANUFACTURE OF TWIST- D RI LLS.

SPECIFICATION forming part of Letters Patent N0. 273,322, dated March6,1883.

7 Application filed May 9, 1881. (N model.)

To all whom it may concern: Be it known that we, ELIAS STRANGE, ELIAS W.STRANGE, and EMERSON G. STRANGE, of

the city of- Taunton, State of Massachusetts,

have invented Improvements in the Manufacture of Twist-Drills, of whichthe following is a specification.

This invention relates to the manufacture of that class of drills knownas twist-drills, which are usually formed by'the process of milling aspiral groove in opposite sides of the drill, so as to produce what areknown as straight cutting-lips and theinvention will, in connection withthe annexed drawings, be hereinafter fully described, and specificallydefined in the appended claim.

In said drawings, Figure l is a side elevation of a power pony hammerwith dies for performing the first or forging step in our process ofmanufacturing said drills. Fig.2 is an enlarged crosssection of adrill-blank as it leavesthe dies of the hammer. Fig. 3 is asideelevation, and Fig. 4 afront elevation, of a pair of rolls by whichthesecond step or stage of our process is effected. Fig. 5 is anenlarged perspective view of the drill-blank after it has been operatedupon by said rolls. Fig. 6 is a cross-section of Fig. 5, showing theblank within the rolls. Fig. 7 is a perspective view of a machine bywhich the twisting or third step in the manufacture of our drills iseffected. Fig. 8 is an enlarged side elevation or plan of the twisteddrill. Fig. 9 is a side elevation, and Fig. 10 a front elevation, of amilling or grinding machine by which the grooves of the drill aresmooth-finished after being twisted. Fig. 11 is a side elevation of amachine by which the drillis ground true and round upon its outside.

In said Fig. 1, (1 represents the bed of the hammer, and b thehelve,'which is pivotally mounted in a standard of bed a, as shown. Saidhelve is actuated in the usual manner by cam-disk c, which is mounted onthe arbor of the fly-wheel d, and upon said arbor a pulley is arrangedfor the actuating thereof by a belt. In

bed a and the front end of helve b are respectively mounted the dies 0,which are formed with such configuration of face thatwhen thedrill-blank, which is a round steel rod of the boxes that are verticallyadjustable in said frames in the usual man ner; Upon the arbor of thelower roll it is secured a pulley, i, and upon the arbor of each roll issecured an enmeshing gear, 70, to insure coincident rotation of saidgears when said pulley is actuated by a belt. After the drill-blank issubjected to the forging or hammering process bythe dies it is nextrolled by means of the rollers h h,-

which are formed with such outline of face as will give a contour ofcross-section similar to that shown in Fig. 6. Said rolls are eitherformed with sufficient eccentricity relatively to their axes or arearranged to have an automatic alternating movement toward and from eachother, in order that the drill-blank, when being rolled, shall receive agradual taper in its thickness from the point of intersection of thecylindrical or shank part and the grooves f to the grooved end of thedrill-blank, in order that it shall have greater strength near the innerends of the grooves than at the front or grooved end. Fig.5 shows thedrill-blank after it has been subjected to the action of rolls h. Afterthe drill-blank has been thus rolled it is next twisted, which may beeffected by the machine shown in Fig. 7, wherein Z is the bed and m andn standards. In standard nis journaled an arbor, 0, wherein is out aspiral groove of the same pitch as that desired in the twist of thedrillj. Pin 8, threaded in standard n, engages in the groove of arbor 0to insure the required relative rotation and lineal movement of thearbor, the same being actuated by the hand-wheel 19. To the oppositestandard,m,is hinged the lever t, coincidently in which and its standardare formed seats corresponding to the half-diameter of the groovedportion of the rolled drill-blank, as shown in the enlarged detachedFig. 12.

To twist the heated drill-blank, it is placed l tions, and so insure afree cut and consequent between lever t and head m, and its shank issecured in arbor o by a set-screw or other means, the inner ends of thegrooves being placed close to the inner face of standard in and leverit, when, by rotating and retracting arbor 0, as described, thedrill-blank will be drawn past lever t and standard m, and will therebyacquire the same pitch of spirality or twist as the groove in said arbor0. After the drill-blank is thus twisted its grooves are finished bygrinding or milling with a rotary cutter, which finishing may beeffected by the machine shown in Figs.9 and 10, in which it represents aframe, in which is mounted, upon a suitable arbor, the grinding orcutting disk 17, driven by'a belt on pulley ll, the drill being movedupon a die or bed, 9!, past the cutter,

. which thereby imparts a uniform finish, depth,

and configuration to the grooves. After the grooves of the drill-blankare thus perfected its exterior is finished, either before or after itis tempered, by grinding, which may be effected by the machine shown inFig. 11, in which so is the bed, from which rise the standards 3 3, uponor in which is journaled the arbor of the grinding-wheel 2, which may berotated by a belt upon pulley 4, secured to its arbor.

In the standards y the arbor w is journaled, which is driven by a beltupon its pulley z; and in this arbor one end of drillj is centrallysecured, while its other end is similarly secured in arbor 6, which isjournaled in standards 5, and is provided with a pulley, 7, for itsrotation by a belt.

The standards 3 may be formed upon or provided with a supplemental bedmoving upon ways both transversely to and in the axial direction ofdrill j, in order that the grindingwheel 2 may be adjusted toward oraway from the drill to insure the requisite diameter thereof, and alongthe length thereof in order to insure a uniform diameter throughout itslength, such movements of the wheel and its supporting-frame being inaccordance with the wellknown method of grinding cylindrical bodies to auniform diameter by means of a rapidlyrotating wheel revolving in thesame direction as the more slowly-revolving body, whereby theircontact-surfaces move in opposite direcaccuracy in the diameter of thebody so ground. The drill, after being finished in its grooves, asdescribed, may be tempered as the next stage, and then ground upon itsexterior, as described, or it may he so ground upon its exterior andthen tempered, as may be preferred, for if tempered last its color willbe dull, but it ground last it will of course be bright.

We are aware that it is a common and almost universal practice to formthe spiral grooves in twist-drills by subjectingthe blanks directly tothe actions of mills or cutters, and we of course make no claim tomilling merely; and we are also well aware that one of the oldest, andperhaps the oldest, methods of forming twist-drills is to form a ribbonof steel of the desired width and thickness, and when heated to twistthe same into a spiral form, to be pointed and tempered to serve as adrill. We are also aware that forging or rolling grooves in metal forvarious purposes and in various configurations is an old and well-knownpractice, and hence we do not claim any of the separate means or methodsemployed by us in manufacturingour drills; nor do we claim any of themachines or devices herein shown, the same being introduced for the moreready explanation of our invention and for the purpose of showing somemeans for carrying the same into effect.

We claim as our invention- The herein-described improvement in the artof making twist-drills, the same consisting in first forging, hammering,orswaging the blanks to impart thereto the incipient grooves, thenrolling the blanks to more nearly finish and consolidate the same, thentwisting the grooved portion of the blank, then milling or grinding thegrooves to perfect the same, and then cylindrically grinding andafterward tempering, or tempering and then grinding the drill, as abright or dull colored finish is required, all substantially asspecified.

ELIAS STRANGE. ELIAS XV. STRANGE. EMERSOLY C. STRANGE. Witnesses:

GEO. R. HUNTLEY, D. L. MITCHELL.

